France's National Front says ex-UMP are heading far right

France's far-right National Front party said Thursday it was having an "explosion" of popularity amid the battle over the leadership of the main right-wing opposition UMP.

The number of members joining the National Front (FN) each day quadrupled amid the UMP crisis to hit 600 a day, according to National Assembly deputy Marion Marechal Le Pen, grandaughter of FN founder Jean-Marie Le Pen.

"We assume that a good number of them are coming from the UMP," she said.

"The French are beginning to realise, based on the explosion of new members, that we are the only real option," Marion Marechal Le Pen said.